Cache is a special type of memory in which frequently used data values and/or instructions are duplicated to reduce latency. When requesting instructions, a central processing unit (CPU) sends a read request. If the data or instructions are located in the cache, the CPU receives the data without delay, which reduces latency. If the data or instructions are not located in cache, the data or instructions are retrieved from higher latency memory. Typically the CPU stands by while the data is retrieved directly and/or stored in cache.